Redding Profile Crimp Dies were designed for those who want the best possible crimp. Profile crimp dies provide a tighter more uniform roll type crimp and require the bullet to be seated to the correct depth in a previous operation. These dies are not for cartridges that headspace on the case mouth. Notes: This die applies a roll crimp to rimmed pistol cases.THESE DIES ARE NOT FOR CARTRIDGES THAT HEAD-SPACE ON THE CASE MOUTH.